A retractor of the aforementioned kind is used, in particular, in operations on the thoracic cage in order to provide access to the heart. Herein the sternum is severed at the center in the longitudinal direction and a spreader arm with the respective at least one retaining element is positioned on each sternum side. By actuating the drive device, the spreader arms are transferred from an unspread position to a spread position along the retraction direction and the sternum held back by the retaining elements is spread open. The spreader arms usually define a spreading plane in which the spreading occurs.
In known retractors, one spreader arm is movable relative to the other spreader arm to which the holding device is rigidly secured. For this purpose, the movable spreader arm is usually connected to a holding arm which is held on the holding device. In order that the spreader arms, in the spread position, can be spaced far enough apart for the surgical intervention, it is necessary, in the known retractors, for the holding arm of the movable retaining device to project at the side to a not inconsiderable extent over the other retaining device. The operating surgeon may find this interfering. Such a holding arm can also prove disadvantageous, in particular, when one sternum half in the spread state is lifted out of the spreading plane and may thereby collide with the holding arm.
An object underlying the present invention is to provide a generic retractor which, having a compact design, is easy to handle.